U.S. Pat. No. 7,537,178 discloses a spinning reel that is for mounting on a fishing rod and that includes a handle assembly, a line guiding rotor, a rotation transmission mechanism that transmits rotation of the handle assembly to the rotor, a spool shaft that is movable back and forth in cooperation with the rotation of the handle assembly, and a spool mounted on the spool shaft and configured for winding of a fishing line by the rotation of the line guiding rotor. The rotation transmission mechanism includes a master gear shaft coupled to the handle assembly, a master gear arranged on the master gear shaft, and a pinion gear that meshes with the master gear. The rotation transmission mechanism employs a constant gear ratio design that may be inadequate for a variety of situations.